LCA4 Gene Therapy Restores Meaningful Vision for Blind Children

MeiraGTx, a genetic medicines company in New York and London, has reported significant vision improvements for 11 children, between the ages of one and four, who received a gene therapy for Leber congenital amaurosis 4 (LCA4), a severe retinal condition caused by mutations in the gene AIPL1. Results for four children in a clinical trial at Great Ormond Street Hospital in London were reported in the journal Lancet. Prof. Michel Michaelides from Moorfield’s Eye Hospital and University College London was lead investigator for the clinical trial and lead author on the Lancet paper.

LCA4 is rare, affecting only a few hundred people in the US and less than 10,000 people globally. By about four years of age, most children with LCA4 have lost virtually all their photoreceptors (rods and cones), the cells in the retina that make vision possible. After that age, AIPL1 gene therapy is not an effective treatment.

Like many other emerging retinal gene therapies, the LCA4 treatment is injected underneath the retina and uses a human-engineered adeno-associated virus (AAV) to deliver copies of the therapeutic gene (AIPL1) into remaining photoreceptors. A single injection is expected to work for many years.

The four children discussed in the Lancet paper had only light perception prior to receiving the AIPL1 gene therapy. After treatment in one eye, they demonstrated improved visual acuity and functional vision, including their ability to perform simple vision-guided tasks. The children also appeared to have protection against progressive retinal degeneration. An additional seven children received the gene therapy in both eyes and had vision improvements similar to those experienced by the first four children treated.

MeiraGtx manufactured its LCA4 gene therapy under a specials license from the Medicines and Healthcare products Regulatory Agency (MHRA) in the UK. A specials license allows a company to make unlicensed medicines for special clinical needs. 

MeiraGTx was also awarded an Innovative Passport Designation for the gene therapy from the MHRA. The designation can accelerate the time to market and patient access. As a result, MeiraGTx hopes to apply for marketing approval in the UK for its LCA4 gene therapy.